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Reference Manual
00809-0100-4027, Rev AA
December 2005
Rosemount 4500
5-2
Table 5-1. Rosemount 4500
troubleshooting table
Symptom Corrective Actions
Transmitter milliamp reading is zero Verify power is applied to signal terminals
Check power wires for reversed polarity
Verify terminal voltage is 11.25 to 30 V dc
Check for open diode across test terminal
Transmitter Not Communicating with
HART Communicator
Verify the output is between 4 and 20 mA or saturation levels
Verify clean DC Power to transmitter (Max AC noise 0.2 volts peak to peak)
Check loop resistance, 250 Ω minimum (PS voltage -transmitter voltage/loop current)
Check if unit is addressed properly
Transmitter milliamp reading is low or high Verify applied pressure
Verify 4 and 20 mA range points
Verify output is not in alarm condition
Verify if 4 – 20 mA output trim is required
Transmitter will not respond to changes in
applied pressure
Check test equipment
Verify applied pressure is between the 4 and 20 mA set points
Verify output is not in alarm condition
Verify transmitter is not in Loop Test mode
Digital Pressure Variable reading is low or high Check test equipment (verify accuracy)
Verify transmitter is calibrated properly
Verify pressure calculations for application
Digital Pressure Variable reading is erratic Check application for faulty equipment in pressure line
Verify transmitter is not reacting directly to equipment turning on/off
Verify damping is set properly for application
Milliamp reading is erratic Verify power source to transmitter has adequate voltage and current
Check for external electrical interference
Verify transmitter is properly grounded
Verify shield for twisted pair is only grounded at one end